Magnetic and Mechanical Properties of Strontium Ferrite and Nd-Fe-B Rubber Bonded Permanent Magnets

Application of permanent magnets bonded by rubber is still growing, especially in the automotive industry. Magnetic and mechanical properties of permanent rubber magnets can be tailored by a production's technology and a magnet's composition. Permanent magnets bonded by rubber are produced by a method called calendaring. Physical properties of rubber bonded permanent magnets depend on a type and amount of hard magnetic powder in a mixture with rubber. Anisotropic strontium ferrite powder and spherical isotropic Nd-Fe-B alloy powder were used in research. The results of measurements show that with an increasing amount of ferrite powder magnetic properties and Shore hardness increase whereas tensile strength decreases. Addition of Nd-Fe-B powder to the mixture instead of some ferrite slightly increases magnetic properties of magnets.